Open Access
Translator Disclaimer
2021 A Gaussian particle distribution for branching Brownian motion with an inhomogeneous branching rate
Matthew I. Roberts, Jason Schweinsberg
Author Affiliations +
Electron. J. Probab. 26: 1-76 (2021). DOI: 10.1214/21-EJP673


Motivated by the goal of understanding the evolution of populations undergoing selection, we consider branching Brownian motion in which particles independently move according to one-dimensional Brownian motion with drift, each particle may either split into two or die, and the difference between the birth and death rates is a linear function of the position of the particle. We show that, under certain assumptions, after a sufficiently long time, the empirical distribution of the positions of the particles is approximately Gaussian. This provides mathematically rigorous justification for results in the biology literature indicating that the distribution of the fitness levels of individuals in a population over time evolves like a Gaussian traveling wave.

Funding Statement

MR was supported by a Royal Society University Research Fellowship, and JS was supported in part by NSF Grant DMS-1707953.


Both authors thank Jiaqi Liu for spotting a typo in an earlier version of the manuscript, and Daniel Fisher for bringing to their attention the references [16, 19, 20]. They also thank two referees for helpful comments that improved the exposition of the paper.


Download Citation

Matthew I. Roberts. Jason Schweinsberg. "A Gaussian particle distribution for branching Brownian motion with an inhomogeneous branching rate." Electron. J. Probab. 26 1 - 76, 2021.


Received: 4 July 2020; Accepted: 27 June 2021; Published: 2021
First available in Project Euclid: 14 July 2021

arXiv: 2006.10798
Digital Object Identifier: 10.1214/21-EJP673

Primary: 60J80
Secondary: 92D15 , 92D25

Keywords: Branching Brownian motion , Evolution , fitness , Gaussian traveling wave


Vol.26 • 2021
Back to Top